Chapter 12 Part 1 Flashcards by amanda kastel

the nervous system includes all the _____ of the body

neural tissue

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what are the basic functional units of the nervous system?

neurons

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what is the function of neuroglia? what is another word for them?

neuroglia are supporting cells, essential to the survival and functionality of neurons AND to preserving the physical and biochemical structure of neural tissue

another name for them = glial cells

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which are there more of — neurons or neuroglia?

neuroglia FAR outnumber neurons

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what are the organs of the nervous system?

-the brain and spinal cord
-the receptors in “complex sense organs” (the ear and eye)
-the nerves that link the nervous system with other systems

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viewed ANATOMICALLY, the nervous system has _____ divisions:

2 divisions:

the CNS (central nervous system) and
the PNS (peripheral nervous system)

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what does the CNS consist of?

the brain and spinal cord

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the brain and spinal cord are complex organs that include….

-neural tissue
-blood vessels
-various connective tissue

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What is the function of the connective tissues in the brain and spinal cord

physical protection and support

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What is the CNS responsible for?

integrating, processing, and coordinating sensory data and motor commands

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Sensory data convey information about what?

conditions inside or outside of the body

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what do motor commands do?

control or adjust the activities of peripheral organs (such as skeletal muscle)

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what is the seat of higher functions, such as intelligence, memory, learning, and emotion?options: CNS or PNS

CNS – specifically the brain

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Explain what is happening with the CNS when we stumble

when we stumble, the CNS integrates information about your balance and the position of your limbs and then COORDINATES your recovery by sending motor commands to appropriate skeletal muscles

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When we stumble and the CNS coordinates our recovery, is this done with your own conscious effort?

no — happens in a split second without our conscious effort

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the PNS includes……

all of the neural tissue outside of the CNS

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What is the function of the PNS?

the PNS:
- delivers sensory information to the CNS
- carries out motor commands to peripheral tissues and systems

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What actually carries the sensory information and motor commands in the PNS?

bundles of axons — called nerve fibers

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these bundles of axons (nerve fibers) are called _________ when they’re associated with blood vessels or connective tissue

peripheral nerves —- or simply nerves

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nerves connected to the brain are called …..

cranial nerves

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nerves attached to the spinal cord are called….

spinal nerves

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describe the 2 basic functional divisions of the PNS

the PNS can be divided into afferent and efferent divisions

the afferent division brings sensory information TO the CNS FROM receptors in peripheral tissues and organs

the efferent division carries motor commands FROM the CNS to muscles, glands, and adipose tissue

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the efferent division of the PNS carries motor commands from the CNS to muscles, glands, and adipose tissue.
What is the term for these target organs?

effectors

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what are receptors? what division of the nervous system are they associated with?

receptors are SENSORY STRUCTURES that either detect changes in the environment (internal or external) OR respond to specific stimuli

they are associated with the AFFERENT division of the PNS – gives info TO THE CNS

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Our receptors range from ____ to _____

slender, cytoplasmic extensions of single cells to complex receptor organs (such as the eye and ear)

Receptors are either ____ or ______ in other tissues

receptors are either NEURONS or SPECIALIZED CELLS in other tissues

divide the PNS further (not just afferent and efferent divisions)

the efferent division of the PNS can be divided into the... SNS (somatic nervous system) ANS (autonomic nervous system) ANS can be divided into a sympathetic division and a parasympathetic division

what is the function of the SNS and what division of the PNS does it belong to

the SNS belongs to the EFFERENT division of the PNS the function of the SNS is to control skeletal muscle contractions.

Are skeletal muscle contractions voluntary or involuntary? explain

skeletal muscle contractions can be voluntary or involuntary voluntary = conscious control. ie: raising your hand involuntary = an automatic response called a REFLEX. ie: putting your hand on a hot stove and immediately removing it BEFORE WE EVEN NOTICE ANY PAIN

Describe the function of the ANS and what division of the nervous system it belongs to

ANS = autonomic nervous system. belongs to the efferent division of the PNS the ANS provides AUTOMATIC regulation of smooth muscle, cardiac muscle, glandular secretions, and adipose tissue, (at the subconscious level)

the ANS can further be divided into....

the sympathetic division and the parasympathetic division

the parasympathetic and sympathetic divisions of the ANS have ___ functions. explain

antagonistic for example, the sympathetic division accelerates the heart rate, whereas the parasympathetic slows it down

What is the most common type of neuron in the CNS? describe its structure

the most common type of neuron in the CNS is the multipolar neuron. multipolar neuron structure: large cell body, several short, branched dendrites, and a single long axon ending in terminal branches called telodendria

what is another word for the cell body

soma

the cell body contains....

a large, round nucleus with a prominent nucleolus

what is the perikaryon?

the cytoplasm surrounding the nucleus of the cell body

do neurons have a cytoskeleton?

yes

the cytoskeleton of the perikaryon contains....

neurofilaments neurotubules

neurofilaments are similar to the _____ of other types of cells neurotubules are similar to the ____ of other types of cells

neurofilaments ~ intermediate filaments neurotubules ~ microtubules

what are bundles of neurofilaments called?

neurofibrils

where do neurofibrils extend to?

neurofibrils extend into the dendrites and axon, which provides internal support for them

____ extend into the dendrites and axon, providing internal support for them

neurofibrils (bundles of neurofilaments)

does the perikaryon of a neuron contain organelles?

(perikaryon = cytoplasm of a neuron) YES

What is the function of the organelles in the perikaryon of the nucleus?

the organelles provide energy and synthesize organic materials ESPECIALLY chemical neurotransmitters that are responsible for cell to cell communication

what give the perikaryon a coarse, grainy appearance?

-the numerous mitochondria -free or fixed ribosomes -membranes of the rough ER

do neurons have a low energy demand?

no -- they have a high energy demand. this is why they have numerous mitochondria to generate ATP to meet these demands

what structure(s) in the neuron synthesize proteins?

the ribosomes and rough ER

what are Nissl bodies?

areas of the perikaryon that contain clusters of rough ER and free ribosomes. these regions stain darkly

Nissl bodies give a ____ color to areas containing neuron cell bodies

GRAY this gives the gray matter seen in gross dissection of the brain and spinal cord

can typical CNS neurons divide? explain

NO they cannot divide. this is because they lack centrioles, which are important to help organize the cytoskeleton AND they lack microtubules that move chromosomes during mitosis

can neurons be replaced if they are lost due to injury or disease?

NO -- they cannot divide

Neural stem cells are only active where?

in the NOSE and in the HIPPOCAMPUS nose -- the regeneration of olfactory (smell) receptors maintains our sense of smell hippocampus -- part of the brain involved in storing memories

TRUE OR FALSE.... neural stem cells persist in the adult nervous system, but they are typically inactive except for the nose and hippocampus

true

what are the slender extensions that extend out from the cell body?

dendrites

dendrites play key roles in _____ communication

intracellular

explain how dendrites play a key role in intracellular communication

dendrites are highly branched, and each branch has processes called DENDRITIC SPINES. In the CNS, a neuron receives information from other neurons primarily at these dendritic spines (these account for 80-90% of a neuron's total surface area)

_______ account for about 80-90% of a neuron's total surface area

dendritic spines

an electrical impulse is also known as......

an action potential

what is an axon?

a long, cytoplasmic process capable of propagating an action potential (electrical signal)

what is the axoplasm and what does it contain

the axoplasm is the cytoplasm of the axon. it contains neurofibrils, neurotubules, small vesicles, lysosomes, mitochondria, and various enzymes

what surrounds the axoplasm?

the axolemma

the axolemma may either be....

exposed to the interstitial fluid OR covered by the processes of neuroglia

the BASE of an axon (closest to the neuron) is called....

the initial segment

what is between the initial segment and the body of the neuron

the axon hillock

what are collaterals?

when an axon branches along its length, producing side branches called collaterals

what do collaterals do?

collaterals enable a single neuron to communicate with several other cells

what are telodendria

fine extensions that end either the main axon trunk or any collaterals that branch off of the axon

what is another word for telotendria

terminal branches

the telodendria end at...

synaptic terminals (also called synaptic knobs)